Field of the Invention
The invention relates generally to dipole antennas and, in particular, to dipole antenna assemblies.
Background Information
A dipole antenna is a well known type of antenna that consists of two radiating elements that are center fed. The two radiating elements operate as positive and negative sides, or halves, of the dipole antenna. Due to the configuration of the antenna (that is, where the ends of the antenna correspond to anti-nodes and the center to nodes), the antenna resonates well.
Dipole antennas are considered balance devices because they are symmetrical and work best when they are fed with a balanced current. In other words, the current is of equal size on both halves (e.g., and phase shifted 180 degrees). When the antenna is fed with an unbalanced feed, such as a coaxial cable, the antenna assembly typically includes a type of circuit or transformer called a balun (from BALanced and UNbalanced).
Generally, a dipole antenna assembly has a “T” shaped configuration, in which the two radiating elements extend outwardly in different directions from one another and are arranged perpendicular to the balun. To increase the bandwidth and/or improve the performance of the dipole antenna, the respective antenna radiating elements may also have various shapes, which increases the width of dipole antenna assembly. The configuration of the antenna assembly and the various shapes of the antenna elements result in dipole antenna assemblies that overall are large and ungainly. While the relatively large overall size and configuration of the assemblies may be suitable for use with many types of devices, the size and configuration are not well suited for use with handheld devices and, in particular, handheld communication devices, which are being designed smaller, thinner and sleeker. Further, the configurations with or without shaped antenna elements are not aesthetically pleasing for such handheld communication devices.